Symptom Guide
Rough idle Symptom Hub
Rough idle often traces back to ignition, air metering, vacuum leaks, or timing-related faults before it becomes a full misfire complaint.
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Related Resources
Repair guides, wiring diagrams, and other pages related to this symptom.
Likely Repair Categories
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Open the repair category that best matches rough idle complaints.
Open the repair category that best matches rough idle complaints.
Open the repair category that best matches rough idle complaints.
Open the repair category that best matches rough idle complaints.
Codes Often Seen With This Symptom
Browse →The engine is running lean on bank 1 — too much air or not enough fuel. The ECM has maxed out its fuel trim trying to compensate. Common causes include vacuum leaks and dirty MAF sensors.
The engine is misfiring across multiple cylinders. This is often caused by something that affects all cylinders — spark plugs, fuel quality, vacuum leak, or low compression.
Cylinder 1 is misfiring — not firing properly. Could be spark plug, coil, injector, or compression issue on that specific cylinder.
Cylinder 2 is misfiring.
The engine computer cannot control the variable valve timing solenoid on bank 1. This affects engine performance and fuel economy. Usually caused by a faulty VVT solenoid or wiring issue.
The intake camshaft on bank 1 is more advanced than the ECM commanded. This typically means the VVT system is stuck or the oil flow is restricted. Often caused by dirty oil or a stuck VVT solenoid.
The intake camshaft on bank 1 is more retarded than commanded by the ECM. This reduces engine performance and efficiency. Often related to oil viscosity issues or a failing VVT actuator.
The ECM detected a fault in the exhaust camshaft VVT solenoid circuit on bank 1. This solenoid controls exhaust valve timing for optimal performance and emissions.
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Related Trouble Codes
These check engine light codes are often associated with this symptom.
Fuel Code
P0171: System Too Lean (Bank 1)
Ignition Code
P0300: Random/Multiple Cylinder Misfire Detected
Fuel Code
P0101: Mass Air Flow Sensor Circuit Range/Performance
Fuel Code
P0103: Mass Air Flow Sensor Circuit High Input
Emissions Code
P0130: O2 Sensor Circuit (Bank 1, Sensor 1)
Emissions Code
P0131: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
Repairs That May Fix This
These repair guides are commonly needed when you experience this symptom.